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Discussion Starter · #1 · (Edited)
Hello everyone.
My R125 decided that it wants to tick after I rebuilt the top end :/
There's no tick when the engine is cold.
It also doesn't tick when idling. Only above 3k RPM
I checked the cam chain tensioner when the top end was apart and it seemed to work just fine.
I'm going to adjust the valves this weekend.
Anyone have any idea if I should check something else?
Thanks for the help :D

Video link:
 

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Discussion Starter · #2 ·
So, I checked the valve clearances today, and they were all perfect, so no problems there.

I also checked the timing of the engine and that was fine too. Now I'm thinking that it's the timing chain tensioner, as those are a bit of a weak part on these bikes iirc.
Riding season starts in 1 day, so I'll just ride it and wait for it to explode :p
 

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Are you saying it's a timing tensioner? then replace it, for example with a non-original replacement. And then check.
Because if you destroy an engine, it will cost you a lot.

Check if the oil reaches the head. You know how to do it right? : D
All parts are tightened with the right torque Nm?



Also, if the ticking appeared after repairing the top, you must have put something together wrongly. Piston rings? securing the piston pin?
 

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Discussion Starter · #4 ·
Are you saying it's a timing tensioner? then replace it, for example with a non-original replacement. And then check.
Because if you destroy an engine, it will cost you a lot.
I think it's the tensioner, as everything else is fine. I rode the bike today and I can't hear any weird noises while riding.
I'll look into getting a new tensioner.
 

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You cannot hear while driving, and something interesting sounds when stationary and hot engine at 3000 rpm.

Let me know if replacing the timing tensioner helped.
 

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Discussion Starter · #6 ·
Ok, so I took out the chain tensioner. Looks like it was at it's maximum length, so my chain is too stretched.
I'm not going to take the engine out again, so I'll just order a manual chain tensioner.
 

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Discussion Starter · #7 ·
I MADE A MISTAKE IN MY ANALYSIS!!!!!

The chain isn't stretched. A friend of mine that knows a thing or two about these engines (he's making a something around 200cc R125 and he's possibly going to turbo it :oops:) said that the problem is most likely the valve rockers, as they do wear out on these engines.

I'll look at the rockers when I have time, but for now it's just making an annoying ticking :D
 

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if your valve clearances are ok, putting a late-model timing chain tensioner on might not be a terrible idea. video on doing that and the differences between the various types of tensioner is here:
 

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It might be the tappets or the fuel injector. you can hear the fuel injector a lot more with the fairings off so you might not have noticed it before, now you just can’t un-hear it 😂
 
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